Why is stormwater detention needed in the Park Hill Golf Course?
The Park Hill drainage basin has a long history of serious flooding issues. Stormwater in this basin generally flows from south to north and empties into the Sand Creek. The rough boundaries of the basin are Quebec Street, Colorado Boulevard, 23rd and 52nd Avenues. There have been reports of flooding and flood damage for years in the northern end of the Park Hill basin. In August 2000, Firefighter Robert Crump died while trying to save a woman from rising stormwater around Colorado Boulevard and 50th Avenue.
To prevent stormwater pipes from being dangerously overwhelmed during large storms, detention areas temporarily hold and then slowly drain stormwater into the pipe system. The vegetation in naturalized detention areas also works to clean stormwater as it makes its way to rivers and streams. During heavy storm events, water naturally flows to the northern end of Park Hill Golf Course, and for this reason, additional detention capacity is being constructed at this location as part of an overall system to improve stormwater management and water quality.
Where is the project located and how much stormwater will it manage?
A stormwater detention area will be constructed within a 25- acre permanent easement in the northeast corner of the Park Hill Golf Course property. Water will enter the detention area via a new stormwater pipe being installed along 39th Avenue that connects to the 39th and Holly Street detention area. Water will be detained for short periods of time (less than 72-hours in the 100-year storm event) before flowing north towards Sand Creek through a new stormwater pipe system being installed along Dahlia Street.
The stormwater detention area in the golf course is being constructed to hold approximately 220 acre-feet of water, which is what is needed to manage up to a 100-year flood event. Upon completion, this construction project will form a “backbone system” that can be built upon in the future to provide greater stormwater protection to homes in Park Hill south of the golf course.
Is this a pond? Will there be standing water in the detention area? What about mosquitos?
Although engineers sometimes refer to these types of stormwater detention areas as “detention ponds,” they are not what we typically think of when we hear the word “pond.” Detention ponds are not intended to permanently hold water; they temporarily hold and slow down stormwater so that the system can manage the water more effectively. The Park Hill Golf Course detention area will temporarily hold water during heavy storm events, and gravity will naturally convey the water into the pipe system at Dahlia Street and Smith Road and then flow to Sand Creek. Most of the time, the detention area will be dry. The maximum time that water will be in the detention area will be about 72 hours.
Mosquitos like to breed in large, shallow pools. The detention area will not be wet long enough for mosquitos to breed as detained stormwater is required by law to drain within 72 hours. Low flow events will be conveyed through a micro pool at the outlet pipe at the corner of Dahlia Street and Smith Road. The micro pool will remain wet as is required to ensure functionality of the outlet structure, however the micro pool is too deep to host breeding mosquitoes.
When will construction begin and how long will it last?
Construction began in December 2018 and is expected to be complete by June 2020. There should be minimal traffic impacts to residents during construction. Business access will be maintained during construction.
Will the construction team be doing soil testing?
An environmental firm is part of the construction team and will be doing soil sampling and create a materials management plan to properly haul and dispose of excavated soil.
How can I get updates during construction? What do I do if I have questions during construction?
Construction updates will be posted regularly to the project website at denvergov.org/plattetoparkhill. To email questions or to receive email updates contact: ParkHillDetention@PublicInfoTeam.com, or call the project hotline at (720) 990-6400. You can also subscribe to our texting service for traffic impact alerts by texting “ParkHill” to 313131.